Process for imparting soil-releasing and anti soil-redeposition properties to textile materials

ABSTRACT

A PROCESS IS DISCLOSED FOR IMPARTING IMPROVED DURABLE SOIL-RELEASING AND ANTI-SOIL-REDEPOSITION PROPERTIES TO TEXTILE MATERIALS CONTAINING NATURAL FIBERS. THE PROCESS COMPRISES APPLYING TO SAID MATERIAL, A TETILE RESIN, A PIGMENT AND A HYDROHOBIC FILM-FORMING POLYMER BINDER, AND CURING SAID TEXTILE RESIN ON SAID TEXTILE MATERIAL. THE TEXTILE MATERIALS TREATED IN THIS MANNER EXHIBIT IMPROVED SOIL-RELEASING AND ANTI-SOIL-REDEPOSITION CHARACTERISTICS UPON REPEATED CLEANING IN EITHER AQUEOUS DETERGENT SOLUTIONS OR DRY CLEANING SOLVENTS.

United States Patent 3,674,548 PROCESS FOR IMPARTING SOIL-RELEASING AND ANTI SOIL-REDEPOSITION PROPERTIES TO TEXTILE MATERIALS Dmitry M. Gagarine, Spartanburg, S.C., assignor to ggering Milliken Research Corporation, Spartanburg,

No Drawing. Filed Apr. 9, 1969, Ser. No. 814,843 Int. Cl. C08j 1/44 U.S. Cl. 117139.5 A 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to textile materials having improved durable soil-releasing and anti-soil-redeposition characteristics, and more particularly to fabrics which have been treated with a textile resin, a pigment and a hydrophobic film-forming polymeric binder. Additional soil-releasing polymeric compositions, and textile resin catalysts also may be included.

In recent years, considerable emphasis has been placed in the textile industry on the finishing of textile materials to prepare wash-and-wear fabrics and durable-press fabrics. For example, in U.S. Pat. No. 3,377,249 there is disclosed a process for imparting soil-release characteristics to textile materials and particularly textile materials which have been given durable-press treatments.

Soil-releasing problems are particularly evident with textile materials containing hydrophobic fibers such as polyester fibers since such materials generally tend to retain stains to a greater degree and to absorb soil from dirty wash water during laundering. There is, therefore, a twofold problem, soil release and soil pickup during washing which will hereinafter be referred to as soil redeposition.

The term soil release is utilized in this application to refer to the ability of a textile fabric to be washed or otherwise treated to remove soil and/or oily materials which have come into contact with the material. The present invention does not completely prevent the attachment of soil or oily materials to the fabric, but hinders such attachment and renders the heretofore uncleanable fabric susceptible to repeated cleaning operations.

Soiling problems are significant in durable-press fabrics as a result of the chemicals which have been applied to the fabric to provide the durable-press characteristics. These characteristics generally have been imparted to the textile material by the application of resinous materials. The resinous materials are applied to the fabric and crosslinked to the fabric by the action of a suitable catalyst. Depending upon the time of the crosslinking reaction, either a wash-and-wear fabric or a durable-press fabric is produced. Precured fabrics are those in which the crosslinking reaction occurs prior to transformation of the fabric into a garment or other article. Wash-and-wear fabrics result. Post-cured fabrics are those fabrics which are subjected to the crosslinking reaction after the fabric has been transformed into a garment or other article thereby producing permanent press. It has been observed,

however, that these garments or articles are easily soiled, regardless of the method of preparation. The incorporation of soil-releasing compositions such as those found in U.S. Pat. No. 3,377,249 provides distinct improvements in the soil-releasing and anti-soil-redeposition properties of the treated fabrics when washed in aqueous media. One of the problems of the above-described treated textile materials is that the soil-releasing chemicals are partially removed from the materials upon repeated washes. Another disadvantage of these treated materials is that they cannot be cleaned in dry cleaning solvents Without substantial soil-redeposition occurring. Since dry cleaning is an important method of cleaning garments such as dress slacks, suits, and industrial fabrics, there has been a distinct need for a treatment which will be durable to such dry cleaning processes.

SUMMARY OF THE INVENTION These problems have been overcome by providing a process for treating textile materials containing natural fibers with a textile resin, a pigment and a hydrophobic film-forming polymer binder, said polymer being formed from' a compound having a polymerizable vinyl group, and curing said textile resin on said material. Where additional soil-releasing characteristics are desired, soil-releasing polymers such as synthetic acid polymers, and low molecular weight polyesters of polycarboxylic acids and polyalkylene oxides, are applied to the fabric in addition to the above materials. It has been found that the combination of a soil-releasing polymer, the pigment and the hydrophobic film-forming polymer binder results in permanent press textile materials having soil-releasing and anti-soil-redeposition characteristics of synergistic proportions in either aqueous or solvent cleaning operations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improvement in the soil-releasing and anti-soil-redeposition characteristics of this invention are obtained when the process is applied to textile material containing natural fibers. The material may be made up completely of natural fibers or may be comprised of a mixture of natural and other fibers, either natural or synthetic. Keratinic and cellulosic fibers are preferred examples of natural fibers. Examples of cellulosic fibers include cotton, flax-linen, cellulose acetate and regenerated cellulose such as viscose rayon. Examples of keratinic fibers include wool, mohair, vicuna, cashmere, etc. Suitable synthetic fibers which may be utilized in combination with the natural fibers in the preparation of the textile materials include synthetic polymeric fibers such as polyamides (e.g., polyhexamethylene adipamide), acrylics, (e.g., polyacrylonitrile) and particularly polyesters and blends thereof. Examples of commercially available polyester fibers include the various types of polyethylene terephthalates such as Dacron available from E. I. du Pont, Fortrel from Celanese, Kodel from Eastman Kodak, and Trevira from Hystron. Durable-press and wash-and-wear garments and articles generally are made from blends of polyester and cotton or rayon fibers. While the textile material undergoing treatment preferably is in the form of a fabric, the process of the invention also may be useful for treating fibers, yarns, threads, etc. Examples of fabrics comprising blends of natural and other fibers which may be utilized in this invention include fabrics comprising 50% polyester and 50% cotton; 65% polyester and 35% cotton; 65% polyester and 35% viscose rayon; wool and 15% nylon; 65% wool and 35% viscose rayon; and 55% Acrilan with 45% wool.

The term textile resin according to the present inven- 1 tion includes both monomers and polymers which when applied to a textile material and reacted under proper conditions undergo polymerization and/or condensation and are transformed to the thermoset state. Textile resins that may be employed when practicing the present invention include epoxy, acetal, aminoplast resins, etc., with the aminoplast resins being preferred. These nitrogen containing resins when applied to a textile material, usually in the presence of a catalyst at temperatures of from 100 C. to about 300 C., are transformed into the thermoset state. The aminoplast resin condenses with the cellulose molecules and when vinyl groups are present in the aminoplast resin, it undergoes addition polymerization with itself and also with the cellulose molecule if irradiated. The cured textile resin on the textile material affords the textile material a durable-press and/or wrinkle resistant characteristic.

Exemplary of the aminoplast resins that may be employed according to the present invention are the urea formaldehydes, e.g., propylene urea formaldehyde, dimethylol urea formaldehyde, etc., melamine formaldehydes, e.g., tetramethylol melamines, pentamethylol melamines, etc.; ethylene ureas, e.g., dimethylol ethylene urea, dihydroxy dimethylol ethylene urea ethylene urea formaldehyde, hydroxy ethylene urea formaldehyde, etc., carbamates, e.g., alkyl carbamate formaldehydes, etc.; form aldehyde-acrolein condensation products; formaldehydeacetone condensation products; alkylol amides, e.g., methylol formamide, methylol acetamide, etc.; acrylamides, e.g., N-methylol acrylamide, N-methylol methacrylamide, N- methylol-N-methacrylamide, N methylmethylolacrylamide, N-methylol rnethylene-bis-(acrylamide), methylenebis (-N-methylol acrylamide), etc.; haloethylene acrylamide; diureas, e.g., trimethylol acetylene diurea, tetramethylolacetylene diurea, etc.; triazones, e.g., dimethy-lol-N-ethyl triazone, N-N'ethylene-bis-dimethylol triazone, halotriazones, etc.; haloacetamides, e.g., N-methylol-N-rnethylchloroacetamide, etc.; urons e.g., dimethylol uron, dihyhydroxy d-imethylol uron, etc., and the like. Mixtures of aminoplast textile resins are also within the scope of the present invention.

Vinyl monomers having dual functionality within the scope of the present invention include acrylamides, e.g., N- methylol acrylamide, N-methylol methacrylamide, N- methylol-N-methacrylamide, N-methylmethylol acrylamide, N-methylol methylene-bis-(acrylamide), methylenebis-(N-methylol acrylamide), etc.; haloethylene acrylamide; and similar compounds which conform to the structural formulae set forth in U.S. Pat. No. 3,377,249.

The amount of the textile resin employed is primarily determined by the ultimate use of garments or articles prepared from the fabric. Very small amounts of the resin will afford some improvement and large amounts even greater improvements, but the larger amounts of resin generally adversely affect the hand of the fabric. Hence, the amount of resin employed is preferably that which will afford good crease retention and fiat dry properties while not adversely affecting the hand. For the purposes of the present invention, the amount of textile resin in the pad bath may vary between about 2 and 30% by Weight. Resin applied to the fabric should be in the range of about 2 to 20% based on the dry weight of the fabric and preferably in the range of about 4 to 9% The pigments utilized in the process of this invention include any of the inorganic pigments, whether natural or synthetic. Examples of inorganic pigments include metallic oxides and sulfides of such metals as titanium, zirconium, magnesium, zinc, silicon, beryllium, cerium, columbium germanium, and aluminum. These inorganic pigments may be either hydrous or anhydrous and they may comprise combinations of metals such as the titanates of barium, zinc, lead, and magnesium. These pigments are discussed in Volume II of Organic Coating Technology, Pigments and Pigmented Coatings by Henry F. Payne, John Wiley & Sons, Inc., New York, 1961.

Although any of the above finely-divided pigments may be utilized in the process of the invention, the various forms of titanium dioxide are preferred especially the rutile form. Particle sizes of greater than 0.15 micron provide optimum results.

As mentioned previously, the pigment is applied to the textile material in the presence of the hydrophobic filmforming polymer binder, said polymer being formed from a compound having a polymerizable vinyl group. Although these polymeric compositions are film-forming, it is not necessary that the film deposited on the textile material be a continuous film. Thus, the term film-forming is used in its broadest sense and is not intended to be limited to continuous films. The film should be hydrophobic so that it is not readily removed from the fabric when subjected to an aqueous alkaline Wash and inert to dry cleaning solvents. Therefore, any vinyl group-containing compound which will polymerize to form such as polymer binder can be utilized. The polymerizable compound may be, for example, a vinyl ester of an aliphatic monocarboxylic acid having from 2 to 8 carbon atoms such as vinyl acetate and vinyl propionate; an acrylic or alkylacrylic ester of an aliphatic monohydric alcohol containing from about 1 to 10 carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, ethyl ethacrylate, etc. Some acid, e.g., acrylic acid, may be present in the binder but this acid should not exceed about 1 to 2% of the binder since the binder then becomes extractible in alkaline solutions. The polymerizable compound may also be a vinyl hetrocyclic compound such as N-vinyl pyrrolidone and N-vinyl pyridine.

Mixtures of any of the above monomers may also be polymerized to provide the desired hydrophobic film-forming polymer binder. Polymers and copolymers of the acrylic esters have been found to provide the best results. Examples of such copolymers include the polymers include the polymers obtained from a mixture comprising about 40'- 60 parts of ethylacrylate, 40-60 parts of butylacrylate and 3 to 5 parts of N-methylol acrylamide. These copolymers are generally prepared utilizing emulsion polymerization techniques and they are characterized as self-crosslinking acrylic emulsions. The use of such self-crosslinking polymers is advantageous in the process of the invention since it generally is unnecessary to subject the treated textile materials to elevated temperatures. A copolymer of this nature is commercially available from Rohm & Haas under the trade designation Rhoplex-K-3.

The amount of pigment and binder applied to the textile materials can vary depending on the nature of the pigment and hinder, the properties desired and the end use of the material. Generally the textile material can contain from about 3 to 10% and preferably from about 3 to 5% of the pigment and up to about 20 or 30% or more of the polymer binder. I

The application of a pigment and the polymer binders described above either simultaneously with or after application of a textile resin to a textile material results in a material having durable-press or wash-and-wear characteristics with improved soil-releasing properties. Addition of either the pigment or the binder alone provides no such improvement.

As mentioned previously, it is possible and often desirable to add a textile resin catalyst to the textile material to catalyze the reaction with the textile substrate. Catalysts employed within the scope of the present invention depend upon the specific textile resin or vinyl monomer that is applied to the textile material. For instance, if the textile resin has a functional group that isreactive under acidic conditions, an acid catalyst is used. Likewise, when a functional group is present that is reactive under basic conditions, a base catalyst is used. Furthermore, both acid and base catalysts may be used when both type functional groups are present in the textile resin. In this instance, the catalyst may be added separately or simultaneously. When added simultaneously, one must be a latent catalyst, i.e., one that will not initiate its reaction during the opposite type reaction, but will be activated subsequently under proper catalytic conditions.

The catalysts useful in acitvating the acid or base reactive groups are those conventionally used to activate the reaction of textile resins containing the same group. Preferably, latent acid or base acting catalysts are utilized, that is, compounds which are acidic or basic in character under the curing conditions. The most common acid acting catalysts are the metal salts, for example, magnesium chloride, zinc nitrate and zinc fluoborate and the amino salts, for example, monoethanolamine hydrochloride and 2-amino-2-methylpropanol nitrate.

The base acting catalyst preferably is a compound which does-not initiate substantial reaction of the base reactive group under normal acid conditions, but does initiate substantial reaction under prescribed conditions such as elevated temperature or some other activating means, as through use of another chemical compound. For example, an alkali metal sulfite can be padded onto the fabric and be decomposed into strongly basic alkali metal hydroxide by including small amounts of formaldehyde in the steam used for curing.

The latent base acting catalyst utilized herein preferably comprises an alkali metal salt such as an alkali metal carbonate, e.g., sodium carbonate, which is neutral to mildly alkaline pH, for example, about 8.5, on the fabric but decomposes at temperatures in excess of about 80 C. to form the stronger base sodium oxide which will initiate substantial reaction at the elevated temperatures utilized during curing. Sodium carbonate may be utilized ,if desired since the pH on the fabric produced by this compound under normal conditions is generally insufficient to initiate the desired degree of reaction at temperatures normally employed. If fabrics containing a base reactive group are maintained at pH levels above about 10, however, degradation occurs so that essentially neutral or mildly alkaline catalysts are preferred when base reactive compounds are utilized.

Suitable base acting catalysts include potassium bicarbonate, potassium carbonate, sodium silicate, alkali metal phosphates such as sodium or potassium phosphates, barium carbonate, quaternary ammonium hydroxides and carbonates, for example, lauryl trimethyl ammonium hydroxides and carbonates and the like.

The amount of catalyst to be utilized is that conventionally used in activating the reaction, for example, up to about by weight of an acid acting catalyst in the application bath with the preferred range being from about 1% to about 7%. A preferred range for the base acting catalyst is again the conventional amount and is generally between about 0.2% to about 16%, preferably about 2% -to 16%. The amount of catalyst to be utilized will further depend in part on the temperature at which the reaction is conducted and the amount of catalyst consumed in the reaction. For example, when base catalysts are utilized and if a highly acidic group is released during the reac tion, the amount of base applied to the textile material shouldbe at least sufiicient to provide an excess of base in addition to that which is consumed by the highly acidic group.

Excellent soil-releasing and anti-soil-redeposition properties are obtained if the fabric also is treated with soilreleasing polymers. Again, there is a, synergistic improvement as a result of the presence of this polymer, the pigment and the binder.

The soil-releasing polymer of the present invention may be selected from a large number of different compounds, for example, acid polymers, low molecular weight poly- "esters of polycarboxylic acids and polyalkylene oxides,

hydrophilic properties and is at least partially insoluble in water. Thefilm if water soluble, would, of course, be easily washed from the fabric. The polymer from which the film is formed may, however, be water soluble if applied with a textile resin, for during the curing process, the polymer if water soluble, is transformed to a water insoluble film. Furthermore, when the polymer is applied to a textile material without a textile resin, it may likewise be water-soluble if the substrate is such that the soil removal is only required once. For acid polymers, an acid content of at least 10 weight percent acid calculated as acrylic acid in the soil-release polymer from which'the film is formed is desirable, andpreferably at least 20 weight percent. It has further been observed that acid polymers that afford soil-release have a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1, and that an air dried film cast therefrom has a Water of imbibition of at least 89% Synthetic acid polymers within the scope of the present invention may be prepared from any of the polymerizable organic acids, i.e., those having reactive points of unsaturation, e.g., one of the acrylic acids. These polymers may be homopolymers of the acids, or interpolymers of an acid and other monomers copolymerizable therewith so long as at least 10 weight percent acid monomer is present in the polymer. Exemplary of polymerizable acids that may be used, are acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, polymerizable sulfonic acids, polymerizable phosphoric acids, etc. Monomers that may be interpolymerized with the acids include any monomers capable of copolymerizing with the acids and which Will not detrimentally affect the film-forming properties of the polymer. Suitable monomers include, esters of the above acids prepared by reacting the particular acid with an alkyl alcohol, e.g., acrylic esters such as ethyl acrylate, methyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylate, 2- ethylhexyl acrylate, butyl acrylate, etc.; alkyl fumarates, maleates, crotonates, cinnamates, etc.; vinyl halides; monomers having vinylidene groups; e.g., styrene, acrylonitrile, methylstyrene; substituted vinyl monomers, e.g., chlorostyrene; butadiene, etc. In all of the polymers prepared from the above listed monomers, there should be at least 10 weight percent acid calculated as acrylic acid. It should be noted that various mixtures of the above polymers Will work according to the process of the present 'll'l'VCIllIlOH and hence should be considered within the scope of the present invention. Furthermore, salts of the acid polymers, e.g., sodium, potassium, lithium, ammonium, etc., will afford the desired soil-release characteristics.

Examples of some of the synthetic acid polymers that may be used according to the present invention are polymerization products of:

ethyl acrylate:acrylic acid,

ethyl acrylatezacrylic acidzacrylamide,

butyl acrylate:acrylic acid,

ethyl acrylatezmethacrylic acid,

ethyl acrylatezitaconic acid,

methyl methacrylatezacrylic acid,

2-ethylhexyl acrylateracrylic acid, acrylamidezacrylic acid,

butyl acrylatezacrylic acidzacrylamide,

ethyl acrylatezacrylic acidzN-methylol acrylamide, ethyl acrylate acrylic acid :styrene,

ethyl acrylatezacrylic acid1hydroxy propyl methacrylate, ethyl acrylatezacrylic acid:divinyl benzene,

ethyl acrylatezacrylic acidrallyl acrylamide,

ethyl acrylatezacrylic acid: glycidyl acrylate,

ethyl acrylatezitaconic acid,

ethyl acrylatezsodium styrene sulfonate,

ethyl acrylatezcrotonic acid,

styrenezacrylic acid,

ethyl -acrylate:acrylic -acid:hydroxy ethyl methacrylate, .hydroxy ethyl methacrylatezacrylic acidzacrylamide, and butyl acrylatezethyl acrylate:acrylic acid.

Soil-release polymers, like the textile resins, give some improvement at very low levels on the fabric. Accordingly, as the amount of soil-release polymer is increased, the ability of the fabric to release soil increases. Thus, the upper limit on the amount of soil-release polymer is determined by economics and resulting adverse effects on the fabric, e.g., the hand of the fabric. Furthermore, practically speaking there is a set range of soil-release polymer dictated by commercial success.

The acid polymers, as a general rule, areemulsion polymers containing varying amounts of solids, normally in the range of about 25 to 50 weight percent. The polymer emulsion should be present in the pad bath or other application medium in the range of about 2.5 to 40 weight percent. Otherwise stated, there should be from about 0.25 to .15 weight percent of acid polymer solids applied to the substrate, based on dry weight, and preferably 1.0 to 7.5 weight percent.

The composition applied to the textile material according to the present invention is not limited to only the possible ingredients heretofore mentioned, e.g., textile resin, textile resin catalyst pigment, the film-forming polymer binder and soil-release polymer. Other ingredients may be added such as, for example, emulsifying agents, dispersat that particular stage of the development. The composition may be sprayed 011 as a liquid; the substrate may be dipped, etc.

In general, the application system is adjusted to provide from 30 to 100 weight percent wet pickup by the fabric from the pad bath. Preferably, however, it had been determined that best results are obtained by providing a wet pickup of from .40 to 60 weight percent from the pad bath.

Separate or simultaneous application of the above indicated components may be employed. For instance, when treating a textile fabric which is to beconverted into work clothes, it may be desirable to have as durable a finish as possible so that the soil-release properties will be as long lasting as possible. In this situation, either a simultaneous addition or a separate addition where the soil-release polymer is added first may be desirable. On

the other hand, where the ultimate article of manufacture is not one that will be washed or cleaned on a weekly basis, for instance, the desirable property might possibly be to have a very superior initial soil-release property. An example would be upholstery for automobiles, seat covers, wall coverings, etc. For these items it may be more desirable to apply first the textile resin pigment and binder, and separately after curing of the textile resin apply the soil-release composition. .It must be emphasized, however, that under such conditions the soil-release properties may be less durable than those attained by the aforesaid simultaneous means of application.

Advantages afforded by the process of the present iiivention are available for textile materials treated in almost any form, e.g., fibers, yarns, threads, fabrics or the ultimate product, e.g., a garment, etc. Garments made from the fabrics treated according to the process of the present invention require no additional steps than those normally required for the preparationof the conventional durable-press garments. In other words, the garment may be folded and pressed on conventional equipment, for example, a Hoffman press..The pressing cycle utilized is standard in the industry and generally involves pressing of the garment for a short period of time, followed by a curing operation in an oven. Alternatively, the garment may be set in a desired configurationunder hot, dry conditions, such as by hot pressing without steaming, for example, at temperatures up to about 300 C. for as long as necessary to cure the resin. 7 In general, the textile resin may be selected from several general types. According to the type of resin selected, one of the following processes may be generally followed to achieve the novel. garments produced by the present invention. In each type of procedure, the methods of application and order. of application of textile resin, pigment, film-forming binder, soil-release composition, catalysts, etc., may be varied as described above.

TYPE I v (1) Apply textile resin having one type of functional group, textile resin catalyst, soil-releasing polymer, pigmen; and binder to fabric.

(2) Dry fabric at a temperature insufficient to initiate catalysis of the textile resin.

(3) Make garment from fabric.

(4) Press garment to produce creases where desired.

(5) Subject garment to temperature sufiicient to cataly'ze and cure the textile resin.

TYPE II ('1) Apply textile resin pigment, binder, and optionally, textile resin catalyst to fabric.

(2) Dry fabric at a temperature insufficient to initiate catalysis of the textile resin.

(3) Apply soil-releasing polymer to fabric.

(4) Prepare garment from the fabric. (5) Press creases where desired in garment. 6) Subject garment to conditions sufficient to cure textile resin.

TYPE III conditions.

Type III may be modified to provide a separate application of the soil-releasing composition. a

In each of the above types of procedures, the ultimate curing may be accomplished prior to the manufacture .of the garment whereby a good wash-and-wear fabric having soil-release and anti-soil-redeposition properties is produced.

While the abOV procedures relate to the process of the present invention being applied to a textile material to afford the textile material soil-release and durable-press or wash-ahd-wear characteristics, other materials may'also be applied to the fabric as desired according to the description herein.

The drying temperatures that are insuflicient to initiate the catalysis are dependent upon the particular catalyst being employed. In general, however, the drying step is conducted at a rate of approximately 10 to 70 yards per minute at temperatures ranging from about 225 to 300 F., preferably in a tenter frame. The drying temperature range being overlaps to some degree with the curing temperature range set forth below. When drying in the overlapping portion of the drying and curing ranges, it is important that there be no premature curing of the textile resin. Time is the prime variable and when drying the substrate in the higher end ofthe drying temperature range,

9 care must be taken to avoid heating the substrate for a time sufiicient to initiate catalysis that would at least partially cure the textile resin.

Irradiation techniques may be employed according to the process of the present invention when a vinyl monomer having dual functionality is applied to the textile material. An insulated core transformer, operated at a potential varying between one hundred thousand and five hundred thousand electron volts may be successfully used to irradiate the textile material. Such a transformer is commercially available from High Voltage Engineering Corporation, Burlington, Mass. The amount of ionizing necessary according to the present invention is at least about 3 electron volts for each ion pair formed. Both high energy particle and ionizing irradiation are useful according to the present invention. The preferred dosage of irradiation according to the present invention is in the range of one thousand rads to one hundred megarads, a rad being the amount of high energy irradiation of the type which results in energy absorption of one hundred ergs per gram of absorbing material. More preferably, the irradiation dosage ranges from about 0.1 to megarads.

Curing of the textile resin is accomplished with mixed synthetic/cellulosic textiles by subjecting the textile material having the textile resin thereon to conditions such that the catalyst initiates a crosslinking reaction and converts the resin to the thermoset state. Temperature is the prime mover and generally a temperature in the range of about 100 to 300 C. is sufficient. The curing medium that supports the necessary temperature may be any substance which is inert to both the fabric and the ingredients applied thereto, e.g., hot air, steam, etc. In the instance where the textile resin possesses two different types of functional groups, there are actually two curing steps, the first being conducted at a temperature lower than the second and insuflicient to initiate the second type of catalysis, e.g., a first partial curing step to initiate alkaline catalysis and a subsequent curing step to initiate acid catalysis and also convert the resin to the thermoset state.

The duration of the various processing steps will depend upon the particular ingredient employed. In each situation, however, the treatment time is that necessary to cause reaction of and/or curing of the textile resin, and preferably, between 0.1 and 30 minutes.

The following examples illustrate preferred embodiments of the present invention but are not intended to restrict the scope of the invention. In the examples, parts and percentages are by weight.

EXAMPLE 1 A plain weave poplin fabric made from 65% Dacron (a polyester fiber manufactured by E. I. du Font) and 35% cotton fibers is padded with an aqueous mixture containing about 18% N-methylol acrylamide (50% aqueous solution), 165% dispersed titanium dioxide (60% solution), 22% of an aqueous emulsion of a self-crosslinking terpolymer comprising approximately 60 parts ethyl acrylate, 40 parts butyl acrylate and 3 parts of N- methylol acrylamide (46% solids) and 0.3% of a silicate anti-foam agent. The padded fabric is squeezed between rollers to remove a sufiicient amount of the aqueous system to leave a 50% wet pickup. The fabric is then dried at a temperature of about 125 C. to a moisture regain level of about 5-8% whereupon the fabric is irradiated at a one megarad dose by passing the fabric through irradiation equipment having an insulated core transformer manufactured by the High Voltage Equipment Corporation of Burlington, Mass. The fabric is washed with warm water and dried in an oven to normal moisture regain.

The dried fabric is padded with an aqueous mixture containing 45% of an aqueous emulsion of a copolymer of 30% ethyl acrylate and 70% methacrylic acid solids), 5% of a catalyst comprising 3 parts of zinc nitrate and 1 part of magnesium chloride, 2% of an ethoxylated monophenol wetting agent and 1% of sodium lauryl sulfate. Sufiicient amount of the aqueous mixture is applied to the fabric to provide a 50% wet pickup, and the fabric is dried at about C. Swatches of fabric are cut from the treated sample, pressed% at about C. (5 seconds steam, 5 seconds bake and 5 seconds vacuum) and thereafter-cured at 150 C. for 10 minutes.

EXAMPLE 2 The procedure of Example 1 is repeated with the exception that the self-crosslinking terpolymer in the second aqueous mixture is replaced by an equivalent amount of a low molecular weight polymer of an ethoxylated terephthalic acid available commercially under the trade name Cirrasol TG from Imperial Chemical Industries.

EXAMPLE 3 The procedure of Example 1 is repeated with the exception that the copolymer in the second treatment comprises 70% ethyl acrylate and 30% acrylic acid.

EXAMPLE 4 The procedure of Example 1 is repeated except that the fabric comprises 65 of polyester and 35% of viscose rayon fibers.

EXAMPLE 5 A plain weave broadcloth weight fabric made up of 65 Dacron and 35% cotton fibers is padded with an aqueous mixture comprising 16% of dispersed titanium dioxide (50% solids), 22% of the terpolymer described in Example 1, 22% of dihydroxy dimethylol ethylene urea, 6 parts of a catalyst mixture composed of 3 parts zinc nitrate and 1 part of magnesium chloride, 1.2% of wetting agents, 40 ml. per 1000 grams of aqueous mixture of Polyestren Blue BR" (a 0.5% solution of a polyester dispersed tinting agent from Southern Textile Chemical Company), 6 ml. per 1000 grams of aqueous mixture of Polyestren Pink B (a 0.5% solution of a polyester dispersed tinting agent from Southern Textile Chemical Company), and 1% of Uvitex EBF, a polyester brightener from Ciba Chemical. The padded fabric is squeezed between rollers to a 50% wet pickup and dried at 125 C. to a moisture regain of 5 to 8%. This fabric is cured by heating at a temperature of C. for 90 seconds and calendered at a temperature of 150 C. under a pressure of 1 ton per linear inch.

The cured calendered fabric is then padded with an aqueous mixture containing 40% of a soil-releasing polymer comprising 30 parts of ethylacrylate and 70 parts of methyacrylic acid (20% solids) and 0.5 of an ethoxylated fatty acid wetting agent. The fabric is squeezed to a 50% wet pickup, vacuum-slotted to 35% and dried at 125 C. This fabric is after-washed with warm Water at 70 C. containing wetting agents and dried at 125 C. The fabric is then shrink proofed using the Sanforizing process.

EXAMPLE 6 The procedure of Extmple 1 is repeated except that the second fabric treatment comprises an aqueous mixture conatining 5% of a catalyst comprising 3 parts of zinc nitrate and 1 part of magnesium chloride. That is, no soil-releasing polymer was applied to the fabric.

The fabrics prepared in accordance with the procedures set forth in the examples are tested for soil-release in aqueous systems according to the following procedures. The soil-release values are determined by comparison with a set of standards having numerical ratings from 1.0 to 5.0, with 1.0 representing no soil removal and 5.0 being complete removal of the soil. The fabrics are stained with mineral oil and/or mineral oil containing dirt. After staining, the soil-releasing properties in aqueous and solvent systems is determined.

the indicated number of washes (first number) and then a single wash to remove the stain. In this way the durability of the chemical finish after these washings is determnied.

Test results also are reported for soil-release and redeposition tests in commercial or industrial dry cleaning procedures where no stain is placed on the fabric initially. In these processes, the fabric is subjected to a wash cycle, rinse cycle and dry cycle. In the wash cycle, a mixture of perchloroethylene, detergent and a small amount of water is pumped through the basket, and the solvent is continuously filtered and reused resulting in some soil redeposition. The rinse cycle utilizes clean solvent. Drying of the fabric is accomplished by tumbling in hot air.

Industrial dry cleaning operations differ from the comabove and comparing the results with untreated or partially treated control fabrics.

The various control fabrics are given the following treatments:

Control fabric:

Treatment A As in Ex. 1 but no T103 or hinder included. B As in Ex. 2 but no TiO or binder included.

C As in Ex. 1 but no Ti included.

D As in Ex. 1 but no binder included.

E As in Ex. 6 but no TiO or binder included. F As in Ex. 6 but no TiO- included.

G As in Ex. but no Tio included.

H As in Ex. 5 but no TiO or binder included.

The results reported in the following tables demonstrate the unexpected improvements obtained.

TABLE 1.SOIL RELEASE AND REDEPOSI'IION TESTS INDUSTRIAL D RY CLEANIN G (THIRTY TIMES) Soil redeposition Sample Fabric rating 1 Product of Example 1. 3. 5 2-.- Product of Example 2 3.3 3... ControlA 1.5 4 1. 0 5 3. 0 6.. 2. 5

TABLE 2.-SOIL RELEASE TEST AQUEOUS DETERGENT CLEANING Soil release rating after number of washes (stained! rated) Sample Fabric 0/1 5/6 10/11 10 Product of Example 1 3. 3 4. 3 4. 5 11.-. ControlA 3.4 4.3 4.0 12 2. 8 3. 1 3. 6 13--- Control D 4.1 4.3 3.7 14. Product of ample 3. 9 4. 8 4. 7 15 Control G.. 3.6 4.7 4.4 H 4. 7 4. 7 4. 0

19 Control F 1. 0 2.6 2.1

The results reported above indicate that the addition of the TiO and binder combines with the soil-releasing polymers to provide soil-releasing characteristics which are synergistic and durable to aqueous and solvent cleaning procedures.

That which is claimed is:

1. A process for imparting durable soil-releasing and anti-soil redeposition properties to polyester/cellulosiccontaining textile fabrics comprising applying thereto an aqueous dispersion comprising:

(a) from about 2 to 30% of an aminoplast textile resin,

(b) from about 0 to 15% of a textile resin catalyst,

to) from about 2 to 40% of an acrylic copolymer prepared from a monomeric mixture comprising an acrylic ester and an acrylic acid,

(d) from about 1 to 20% of a titanium dioxide pigment, and

(e) from about 1 to 40% of a hydrophobic film-forming self-cross-linking acrylic ester polymer binder; and heating said fabric to a temperature from about to 200 C. for about 1 to 30 minutes.

2. The process of claim 1 wherein the acrylic ester polymer binder is a terpolymer of ethyl acrylate, butyl acrylate and N-methylol acrylamide.

3. The process of claim 1 wherein the aqueous dispersion also contains a dispersant.

4. The process of claim 1 wherein the dispersant is a neutralized polyacrylic acid or a glycol.

5. The process of claim 1 wherein the textile fabric is a polyethylene terephthalate/cotton material.

6. The process of claim 1 wherein sufficient aqueous dispersion is applied to the fabric to provide up to about 5% by Weight of pigment and from about 5 to 10% by weight of film-forming polymer binder on the cured textile fabric.

7. A polyester/ cellulosio-containing textile fabric containing an aminoplast textile resin, a titanium dioxide pigment, an acrylic copolymer prepared from a monomeric mixture comprising an acrylic ester and an acrylic acid and a hydrophobic film-forming self-crosslinlcing acrylic ester polymer binder.

References Cited UNITED STATES PATENTS 2,790,737 4/1957 Kienle et al 117-161 2,788,295 4/1957 Cooke et a1 117-469 3,004,868 10/1961 Sumner et al. 117-l40 3,066,109 11/1962 Hechtman et a1. 1l7140 X 3,322,569 5/1967 Faulhaber et al. 1r17-143 X 3,377,249 4/1968 Marco 8l15.6 3,420,699 l/ 1969 Sz.Mard et al 117143 X 3,459,716 8/1969 Schaefer et al. l.l7139.5 X 3,491,051 1/1970 Elkin et al 117-l39.4 X

MURRAY KATZ, Primary Examiner T. G. DAVIS, Assistant Examiner US. Cl. X.R. 

